1. Technical Field
The present invention relates to an innovate design of a feeding system of an applicator in a terminal making machine, which serves to automatically feed flexible printed circuits, flexible flat cables and so on for crimping terminals thereon.
2. Description of Related Art
A terminal crimping machine is known to combine metal terminals with stranded wire or a copper cord covered by the metal terminals in a mold so as to establish electric connection between electrode ends or signal ends of the terminals and the wire or cord.
Presently, flexible printed circuits and flexible flat cables have been widely used in electrical machinery, electronic and computer-related fields for electrodes or signal transmission. The so-called flexible printed circuit (also known as FPC) is made by coating copper foil on a flexible polyimide (PI) or polyethylene terephthalate (PET) substrate, and etching the copper foil to create a single-sided, double-sided or multilayer circuit that is flexible, on which circuit electronic devices or press buttons may be added. Such a light and compact flexible printed circuit can be implanted into various electric and electronic apparatuses in a space-saving manner. On the other hand, the so-called flexible flat cable (also known as FFC) is made by combining an insulating material such as PET and a very thin flat tinned copper wire in a high-tech automated wire making machine into a flexible flat cable that acts as a transmission medium for electricity or signals in various electric and electronic apparatuses.
Both flexible printed circuits and flexible flat cables enjoy the advantages of softness, capacity for being bent and folded, small thickness, compactness, easy connection and disconnection, and usefulness for addressing electromagnetic interference (EMI). Therein, flexible printed circuits are suitable applications where special requirements are made to compactness or curved profiles, and may be equipped with electronic devices such as connectors, resistors, capacitors, light-emitting diodes and touch switches, in addition to circuit layouts, so as to act as electronic components with specific functions but not only connecting members. By comparison, flexible flat cables are more economical than flexible printed circuits under cost considerations, and thus are extensively used for electric connection or signal connection between various circuit boards.
For connecting with other connecting members, such a flexible printed circuit/flexible flat cable B must have its copper-foil/copper-wire connecting end B1 be crimped together with terminals A1, and have plural terminals such processed inserted into a plastic housing to form a finalized FPC/FFC assembly.
As shown in FIG. 1 and FIG. 3, in the course of fabricating the terminals, for facilitating its assembling to a copper-foil/copper-wire connecting end B1 of a flexible printed circuit, a flexible flat cable, a normal flat cable or a wire B through crimping, a continuous terminal band A is made of a metal sheet by means of a precise in-mold punching process. The continuous terminal band A has a plurality of equidistant terminals A1, pitch-setting hole A2 and band-positioning portions A3. Each said terminal A1 has one end formed with piercing legs A11 and an opposite end formed with a square-headed contacting section A12 or a U-headed contacting section A13 for connecting a male terminal. At a reverse side of the piercing legs A11 and the square-headed contacting section A12 or the U-headed contacting section A13, there is a clip A14 for engaging with a plastic housing of the resultant terminal connector. However, it is difficult to ensure the precise combination between the copper-foil/copper-wire connecting end B1 of the flexible printed circuit/flexible flat cable B and the terminals A1 through the crimping process. Currently, specialized terminal crimping machines are used for the crimping process to crimp one terminal one time.
The foregoing terminal A1 may have its contact region formed into the contact specifications of either the square-headed contacting section A12 or the U-headed contacting section A13. Therein, the square-headed contacting section A12 requires relatively large band length for forming the square frame of the contact region. In this case, for punching the continuous terminal band A, the adjacent terminals A1 are spaced by a distance D1 of 5.08 mm. On the other hand, the U-headed contacting section A13 only requires relatively small band length for forming the semicircle or U-shaped frame of the contact region. In this case, for punching the continuous terminal band A, the adjacent terminals A1 are spaced by a distance D2 of 2.54 mm. However, in practice, on the connecting end B1, an interval between two adjacent said terminals A1 is set as 2.54 mm.
Thus, clearly, when the continuous terminal band A having U-headed contacting sections A13 is to be combined with the flexible printed circuit/flexible flat cable B with the set intervals of 2.54 mm, plural abreast terminals A1 can be processed at one time. However, when the continuous terminal band A with square-headed contacting sections A12 is to be combined with the flexible printed circuit/flexible flat cable B, it is impossible to crimp plural abreast terminals A1 at the same time. For instance, to make a 13-pin assembly, the conventional crimping method is to feed the terminals with a feed pitch of 5.08 mm and otherwise feed the flexible printed circuit/flexible flat cable B with a different feed pitch of 2.54 mm. By setting the terminal making machine for a 13-pin crimping process and activating it, the terminal making machine will crimp one pin a time until the total 13 pins are finished. In such a case, the biggest concerns are the feeding accumulated error evolving through the 13-pin crimping process and high material loss (and in turn the low yield) due to jams and/or deviation of the terminals or the flexible printed circuit/flexible flat cable B. In addition, the operation is complicated and preciseness is difficult to secure. Moreover, various jigs and crimping molds are involved in the crimping process. Thus, even for crimping terminals of the same specification, several procedures with use of different jigs/molds have to be done, and consequently incur high processing costs, unstable product quality as well as very high defective rate.
In view of the above shortcomings, the inventor of the present invention has invented the disclosed device, which allows continuous terminal bands A with both square-headed contacting sections A12 and U-headed contacting sections A13 to be automatically fed and later crimped with flexible printed circuits/flexible flat cables.